Cell motility suppressed by Snail knockdown. (A and B) Five days after transfection with control siRNA (NC) or Snail siRNA (#1), Panc‐1 cells (A) and IMR90 cells (B) were subjected to Boyden chamber assays. (C) Panc‐1 and IMR90 cells were mixed on a plate, cultured for 1 day, and transfected with control siRNA or Snail siRNA (#1). One day later, the mixed cells were seeded onto collagen‐coated Boyden chambers, and the cells that invaded the lower surfaces of the filters were counted. (D) IMR90 cells transfected with control siRNA (NC) or Snail siRNA (#1) were mixed with collagen gel and added to a Boyden chamber (shown in orange in upper panel). After Panc‐1 cells preinfected with GFP (Panc‐1‐GFP) were transfected with control siRNA (NC) or Snail siRNA (#1), the cells were seeded onto collagen gels containing IMR90 cells. Ten days later, Panc‐1‐GFP cells that had invaded the lower surfaces of the filters were counted. Results are representative of three experiments. Each value represents the mean ± SD of triplicate determinations from a representative experiment. Similar results were obtained from three independent experiments using cells transfected with control siRNA or Snail siRNA (A–D). *P < 0.05, **P < 0.01, ANOVA test.